12.6.9 Text areas in HTML export

An alternative way to publish literal code examples in HTML is to use text
areas, where the example can even be edited before pasting it into an
application. It is triggered by :textarea attribute at an
example or src block.

You may also use :height and :width attributes to specify the
height and width of the text area, which default to the number of lines in
the example, and 80, respectively. For example